Mosquitoes are well recognized as the most important arthropod vectors of disease-causing pathogens. This is because most species are anautogenous and must feed on the blood of a human or other vertebrate to produce eggs. Multiple cycles of blood feeding and egg development in turn favors frequent contacts with hosts, which makes mosquitoes ideal vectors for pathogen transmission. Since disruption of egg production also disables pathogen transmission, understanding the reproduction of anautogenous mosquitoes is an important area of study. This application is a renewal request to continue our work on how egg development is regulated. Our current award focuses on Aedes aegypti, which is the species we best understand how egg maturation is regulated. Our studies indicate that two neurohormones, ovary ecdysteroidogenic hormone (OEH) and insulin-like peptides (ILPs) from the brain, function as key regulators of the egg development process. However, we also have found that OEH but not ILPs is also able to stimulate egg formation in the absence of blood feeding. To advance these results, we need to better understand OEH function in Ae. aegypti, other anautogenous species like Anopheles gambiae, and non-blood feeding autogenous species like. Our Specific Aims to meet these goals are: 1. Characterize OEH mediated nutrient mobilization and egg maturation in Ae. aegypti. 2. Assess the roles of OEH and ILPs in egg development of An. gambiae and O. atropalpus. 3. Assess the effects of OEH, ILP3, rapamycin and insulin receptor inhibitor PQIP in disabling mosquito reproduction. Expected outcomes of our work will include an enhanced understanding of how egg production is regulated in anautogenous and autogenous species. Our study will also provide important insights into how egg development can be disabled. PUBLIC HEALTH RELEVANCE: Mosquitoes are the most important arthropod vectors of disease-causing pathogens. Our work will help us understand the mechanisms that control blood feeding and egg production in mosquitoes, which are critical issues in transmission of disease-causing parasites. This will provide the foundation for development of new approaches for controlling mosquito reproduction and reducing disease transmission.